1. Field of the Invention
The present invention relates to a pneumatic radial tire which is excellent in a durability of a bead portion.
2. Description of the Related Art
Conventionally, in a pneumatic radial tire, particularly in a tire which is used in a heavy vehicle such as an industrial vehicle, a construction vehicle or the like, there is fear that a malfunction such as a separation or the like comes about while beginning at a winding end of a carcass ply which is wound up around a bead core, and a provision of a chafer is generally carried out for improving a durability of a bead portion. The chafer is arranged around the bead core in such a manner as to wrap around a carcass ply from an inner side to an outer side in a tire width direction (refer, for example, to Japanese Unexamined Patent Publication No. 53-119501, Japanese Unexamined Patent Publication No. 5-319035, Japanese Unexamined Patent Publication No. 6-191240, and Japanese Unexamined Patent Publication No. 2005-297927).
Further, the inventor of the present invention has obtained such a knowledge that it is possible to reduce a stress concentration onto a winding end of a carcass ply so as to suppress a generation of a separation by arranging an inner end of a chafer which is positioned in an inner side in a tire width direction, in an outer side in a tier radial direction than the winding end of the carcass ply. And, arranging the chafer as mentioned above is disclosed in Japanese Unexamined Patent Publication No. 53-119501, Japanese Unexamined Patent Publication No. 5-319035, and Japanese Unexamined Patent Publication No. 2005-297927. However, in the case mentioned above, it has found that a trouble such as a separation or the like tends to be generated while beginning at the inner end of the chafer.